Electric switch



Feb. 21, 1933. G JOHNSON 1,898,186

ELECTRIC SWITCH Filed March 12, 1952 mg i 54 ,ve'71/iv7', Kev/ aym Patented Feb. 21, 1933 UNITED STATES PATENT GFFICE GUSTAF A. JOHNSON, OF NEW BEDFORD, MASSACHUSETTS.

ELECTRIC SWITCH Application filed March 12, 1932. Serial No. 598,420.

l also exists in various other forms of lighting fixtures but switches of this compact and shallow construction have come to be known in the art as canopy switches.

One of the objects of the invention is the provision of a switch construction capable of being embodied in a very small shallow and compact structure for use as a canopy switch.

Another object of the invention is the provision of an etlicient structure of extreme simplicity comprising few parts.

A further object is the provision of a,

switch structure in which the various parts may be rapidly assembled without requiring the use and manipulation of screws or similar fastening means.

An additional object is the provision of a switch which can be manufactured at an extremely low cost.

Other objects of the invention will be more specifically set forth and described hereinafter.

My invention contemplates a switch structure which is capable of embodiment in a switch of very small size such as a canopy switch and one of the features of my invention contributin to this end consists in providing an insulating body carrying fixed contacts which are fastened to the lead wires at or adjacent the center of the body. Because of the small size of these switches, it is necessary to provide them with short lead wires which are attached to the fixed contacts in the assembling of the switch structure and which project from the sides thereof for connection to wire conductors. These lead wires are generally insulated with rubber enclosed in a woven textile covering and to prevent the covering from unravelling to expose the wires. it has been customary not only to attach the wires to the, fixed contacts but to bind the ends of the insulating covering within the switch structure. Heretofore, in switches of this character, lead wires have generally been attached to the outer edges or to outer extensions of the fixed contacts which necessitated an extension of the insulating body in order to provide suitable spaces or grooves for enclosing the insulated ends of the lead wires withinthe switch structure. By attaching the lead wires to the inner sides of the fixed contacts at or near the center of the insulating body, I am enabled to produce a switch of much smaller dimensions than would otherwise be possible.

Another feature of my invention resides in producing a construction in which arcing is reduced to a minimum and this is accomplished by the provision of a movable contact positively operated to break the circuit at two points simultaneously to weaken the arc and in a direction transversely the fixed contacts to shorten the arc. One of the principal diiiiculties encountered in the manufacture of canopy switches, because of their small size, is the prevention of undue arcing which is apt to burn out the contacts and shorten the life of the switch and many constructions are of such form that this cannot be adequately prevented.

Various other features of my invention will be hereinafter pointed out and described all of which contribute to the production of a switch which, in spite of its small size, is most eiiicient and durable.

In the accompanying drawing showing one embodiment of the invention for the purpose of illustrating the same, Figure 1 is a side elevation of a canopy switch constructed in accordance therewith and mounted in a canopy; Fig. 2 is a central vertical sectional view of the same on line 2-2 in Figure 1 with certain parts in elevation; Fig. 3 is a central vertical sectional View on a plane perpendicular to the plane of Fig. 2; Fig. 4 is a side elevation of the switch with the means for fastening it to the canopy removed and looking from right to left in Fig. 1; Fi 5 is a bottom plan view of the switch; Fig. 6 is a top plan view of the insulating body showing the fixed contacts and lead wires; Fig. 7

. therefrom, a disk 81 is a bottom plan of the same; Fig. 8 is a top plan view of the rotary contact; Fig. 9 is a side elevation of the same looking upwardly in Fig. 8 and Fig. 10 is a view in perspective of a fixed contact.

Referring to the drawing, designates an insulating body which may be made of any suitable moldable insulating material but preferably is of porcelain. The body may be of any suitable form but is shown as circular because it can be made more compactin that form and occupy less space. In its upper face, the body is provided with a recess 16 in the center of which is a projecting annular boss 17 and the floor of the recess which is of annular form is molded into an annular series of ratchet teeth 18 which in the fo m shown numbers four. (3n the bottom face of the insulating body is formed a pair of oppositely arranged grooves 19 having their inner ends enlarged and commun cating by slots 20 with opposite ratchet teeth in the switch chamber. A pair of contacts 21 (Fig. 10) are mounted within the recess and overlie alternate "eeth and each contact is provided with a pair of lingers 22 turned dow riiardly to project through a slot 20 into a groove 19 to permit one end of a lead wire to be inserted between the lingers and soldered thereto. The enlarged portion of each groove 19 affords room for the solder which looks the contact firmly on its seat. Each lead wire is covered with insulation including the woven covering and the groove is sufficiently wide to receive the insulation when slightly compressed up to the point of soldering; (Fig. 7) so that when the switch is assembled. the end of the insulation will be confined and there will be no danger of the covering unravelling to expose the lead wire at a point outside the switch. To further 111- sure this result the bottom of the groove may at the margin of the body he provided with a projecting lip 25 to grip the insulat d lead wire more firmly. The fastening of the lead wires to the terminals holds them in fixed position on opposite ratchet teeth in the recess of the insulating bod Y and that body with the contacts and terminals may then be treated as a unit in the assembling process.

The insulating body is enclosed by a cas ing which ma be of metal or other suitable material and to insulate the switch parts of suitable insulating material is placed upon the bottom face of the insula ing body 15 and an insulating member 33 in the form of a washer is mounted on the top face of the said body. The casing is provided in its top surface with a central aperture in which is fastened a sleeve having an exterior thread.

lVithin the switch chamber 16 is mounted loosely a movable contact 36 having a central portion provided with a square aperture 37 and adapted to ride on the annular projection or boss 1'? and provided with oppositely extending depressed wings 38 adapted to engage the fixed contacts for closing the circuit (Figs. 8 and 9). Since the top surfaces of the fixed contacts 21 which overlie opposite ratchet teeth are slightly inclined t ne wings of the movable contact are given a corresponding inclination (Fig. 9) in order that they may make a flat engagement with the fixed contacts wnen turned into proper posi- Mounted in the sleeve is a spindle e0, square in cross section, the lo er end of which posses through and fits the square aperture in the movable contact and rests within the interior of the annular projection or boss 17. The upper end of the spindle fits into a square bore in a fluted linger-piece of insulating material which is mounted in and projects from the. upper end of the sleeve. That end of the sleeve has an inwardly projecting flange 43 which acts as an abutment for engaging an enlarged portion l5 on the finger-piece to prevent the lingerpiece from being withdrawn from the sleeve. The spindle, abutt' at its lower end, the floor of the interior recess in the boss 17 and at its upper end the end of the bore in the linger-piece holds the latter in outward position where it may be turned by the fingers to rotate the movable contact. The lower end of the spindle may be provided with a round restricted extension 46 projecting into a central hole within the annular boss 17 to act a guide to prevent any late 'al movement of the lower end of the spindl To hold the movable contact in engagement with the ratchet teeth or fixed contacts yet permitting it to rise thereover when rotated, a helical spring 50 is mounted on the spindle, which spring is under compression at all times abutting at its upper end the inner face of the linger-piece and at its lower end the central portion of the movable contact. Preferably the latter is provided with an upwardly extending flange 52 around the square aperture 37 which flange centers the lower end of the spring on the contact.

For holding the various parts of the switch within the casing. its lo ver ed e is crimped around the periphery of the insulating d sh 31 and'to prevent buckling of the edge in th s operation, it may be scalloped. V

For fastening the switch in a canopy (i l as shown in F 2. too latter is provided with a circular hole of a size to accommodate the sleeve portion of the switch and it then mounted within the canopy ith its slccrc projecting outwardly through the hole, 1 which position it fastened by washer and lock nut 66 threaded on the sleeve. though the lead wires extend from opposite sides of the casing which is provided suitable openings 6?, they may be bent in any direction for attachment to conducting wires or to line terminals. The casing hugs the inner face of the canopy and in consequence, the switch, because of its diminutive size, occupies very little space and can be installed in fixtures of comparatively small size. A switch COHSQILlCtGCl in accordance with my invention can be used in a casing approximately half an inch in width and five'sixt-eenths of an inch in depth.

It will be observed that other than fastening the lead wires to the fixed contacts, the assembling of the switch parts in the sleeved casing requires no fastening means or operations since the parts assembled loosely in operative relation and are maintained in that relation by crimping the lower edge of the casing over the insulating disk. This greatly facilitates the assembling operation, since the sleeved casing may be mounted in reversed position in a suitable support and the parts may be rapidly inserted therein in their prop or relation and fastened by the crimping operation.

The switch is operated to close or to open a circuit by rotating the finger piece preferably in a clockwise direction which rotates the movable contact to move the contact wings either into or out of engagement with the fixed Contact Rotation in an opposite direction is prevented by the engagement of the rear ends of the wings with the vertical shoulders of the ratchet t eth so that the finger piece can be turned only in one direction. in some constuctions, it has been customary to screw the finger piece to the spindle or other operating member which results in the finger piece becoming separated therefrom when t "'ned in the opposite direction but I avoid t disadvantage by locking the finger piece within the sleeve.

In the operation of the switch, assuming the wings of the movable contact to be in engagement with the fixed contacts, the turning of the finger piece turns the movable contact and causes the same to rise against the compression of the spring as the wings move upwardly on the inclined surfaces of the fixed contacts. Any undue upward movement of the movable contact which might cause a short circuit is prevented by the circular washer 33 since its central hole is smaller than the interior diameter of the sleeve. As the wings in their continued rotation pass off the fixedcontacts simultaneously, the spring forces the contact downwardly and the wings drop into the next teeth, thus breaking the circuit by a movement transversely to the fixed contacts. This movement reduces the arcing to the minimum because the arcs instead of being lengthened, as they would be by a separation in a longitudinal direction, are smothered by the porcelain teeth underlying the fixed contact-s.

Although my invention is exemplified herein by a canopy switch, it is not to be limited thereto since it may be embodied in switches of various sizes and shapes. be understood that the invention may be embodied in other forms than that herein shown and described and that the invention is therefore to be construed in the light of the following claims.

WVhat I claim is: p

1. In an electric switch, an insulating body provided with a recess in its upper face having an annular series of ratchet teeth and provided with a pair of grooves in its lower face communicating with said recess, a pair of fixed contacts mounted in said recess on alternate teeth and having portions projecting into said grooves, lead wires in said grooves connected to said projecting portions, a movable contact mounted in said recess and having portions adapted to engage said fixed contacts to close the circuit, a pair of insulating disks for covering the top and bottom faces of said body, said top disk having a central aperture, a casing enclosing said body and said disks to lock the same together, a sleeve centrally located on said casing, a rotatable operating member of insulating material mounted in the upper end of said sleeve and locked therein and means whereby the rotation of said operating member rotates said movable contact to operate said switch.

2. In an electric switch, an insulating body provided with a recess in its upper face having an annular series of ratchet teeth and having oppositely disposed grooves in its lower face communicating with said recess, a pair of fixed contacts mounted in said recess on alternate ratchet teeth and having portions projecting into said grooves, lead wires in said grooves connected to said projecting portions, a movable contact mounted in said recess, means for insulating the top and bottom faces of said body, a casing partially enclosing said body and having a central aperture in its top face, a sleeve fixed in said aperture, a rotatable operating member of insulating material mounted in the upper end of said sleeve and means whereby the rotation of said operating member rotates said movable contact to close and to open the circuit.

3. In an electric switch, an insulating body provided with a recess in its upper face, the floor of which is in the form of an annular series of ratchet teeth, and having oppositely disposed grooves in its lower face communr latin disks for coverin the to and bottom" e g P It is further to faces of said body, said top disk having a-central aperture, acasing enclosing said body and said disks to lock the same together, a sleeve centrally located on said casing, a re- -tatable operating member of insulating matea pair of grooves in its lower face, each of said grooves communicating with alternate ratchet teeth, a pair of fixed contacts mounted in said recess on alternate teeth and having portions projecting into said grooves, lead wires in said grooves connected to said fixed contacts, a rotatable contact mounted in said recess, means for insulating the top and bottom faces of said insulating body, a casing for holding said parts locked together, said casing havin an aperture in its top face, a threaded sleeve fixed in said aper ture, a switch operating member projecting from the end of said sleeve and locked therein against separation from said sleeve and means operated by said member for turning said rotary contact to open and close the circuit.

In an electric switch, an insulating body having a recess in its upper face with a cen tral annular projection, a pair of fixed contacts in said recess, a movable contact mounted to ride on said annular projection for bridging said fixed contacts, said contact having a central square aperture, a sleeved I casing enclosing said insulating body, means for insulating said contacts from said casing, projecting switch operating member mounted in the upper end of said sleeve and locked against withdrawal therefrom, a a square spindle interposed between said operating member and said annular )lOjCCtlOD, the lower end of said spindle fitting said square aperture in said movable contact and a spring interposed between said operating member and said movable contact for bolding the latter in operative position.

(5. In an electric switch, an insulating body having a recess in its upper face witl'i a central annular projection and a pair of grooves in its lower face communicating with said recess adjacent the center thereof. a pair of fixed contacts in said recess, each of said contacts having a portion projecting into one of said grooves. a pair of lead wires laid in said grooves and fastened to said contact project ing portions to lock said fixed contacts in position, rotatable contact loosely mounted on said annular projection for bridging said fixed contacts, a casing enclosing said body, said casing having a central aperture, a sleeve fastenedin said aperture and means mounted in'said sleeve for rotating said movable contact.

7. an electric switch comprising an insulating body recessed in its upper face, said recess having a central annular projection, a pair of fixed contacts mounted in said recess in separated relation, a movable contact for bridging said fixed contacts, said movable contact having acentral square aperture and being loosely mounted on said annular projection, a sleeved casing enclosing said insulating body, the outer end of said sleeve being provided with a flanged opening, a finger piece loosely mounted in said sleeve and projectin from the end thereof, said finger piece having an enlarged flange for abutting the flange in said sleeve to hold said finger piece therein, a square spindle interposed between said annular projection and said linger piece and fitting the square aperture in said movable contact for rotating said contact and a spring on said spindle for maintaining said movable contact in operative position.

8. in electric switch comprising an insulating body having an annular recess and a central hole in its upper face, a pair of fixed contacts mounted in said recess, a movable contact for bridging said fixed contacts, said movable contact having a central square aperture in register with said central hole, a casing enclosing said insulating body and having a central aperture, a s eeve fastened in said aperture, the outer end of said sleeve being provided with a flanged opening, a finger piece loosely mounted in said flanged opening and locked therein against withdrawal, said linger piece having a central square bore in its base, a square spindle interposed between said finger piece and said body with one end fitting said square bore and the other end mounted in said central hole, said spindle passing through and fitting the square aperture in said movable contact, and a helical spring mounted on said spindle between said finger piece and said contact for holding the latter in operative position.

9. An electric switch comprising an insulating body having a recess and a central hole in its upper face, a pair of fixed contacts mounted in said recess, a movable contact for bridging said fixed contacts, said movable contact having a central square aperture in register with said hole, a casing enclosing said insulating body and provided with a central aperture, a sleeve fastened in said central aperture, a finger piece rotatably mounted in the end of said sleeve and locked against withdrawal therefrom, said finger piece havinga central square bore in its base, a square spindle interposed between said linger piece and said body with one end fitting said square bore and the other end said central hole, said spindle passing through and fitting the square aperture in said movable contact and a helical spring mounted on said spindle for holding said contact in operative position.

10. In an electric switch, an insulating body having a recess in one face and a groove in the opposite face communicating with said recess, a contact fixed in said recess and having a portion projecting into said groove and an insulated lead wire laid in said groove and fastened to said projecting portion of said contact and extending outwardly from the side of said body.

11. In an electric switch, an insulating body having a recess in one face and a pair of grooves in the opposite face communicating with said recess adjacent the center of said insulating body, a pair of fixed contacts mounted in said recess, each contact having a portion projecting into one of said grooves and insulated lead wires laid in said grooves and fastened to said projecting portions.

12. In an electric switch,an insulatingbody of disk form having an annular recess in one face to afford a switch chamber and grooves on its opposite face communicating with said recess adjacent the center of said body, a pair of contacts mounted in said recess, each contact having a portion projecting into one of said grooves and lead wires laid in said grooves, each of said lead wires being connected to a projecting portion of one of said contacts.

13. In an electric switch, an insulatingbody circular in outline and having a circular recess in one face thereof and a pair of grooves in the other face communicating with said recess adjacent the center of said body, a pair of quadrant contacts mounted in said recess and having portions projecting into said grooves and an insulated lead wire mounted in each of said grooves and connected to the projecting portion of one of said contacts.

14. In an electric switch, an insulating body of disk like form provided with an annular recess in one face and with a pair of grooves in its other face communicating with said recess, the floor of said recess being in the form of ratchet teeth arranged in an annular series, a pair of contacts mounted in said recess on alternate ratchet teeth, each contact having a portion projecting into one of said grooves and an insulated lead wire in each groove attached to said projecting portion of one of said contacts.

In witness whereof, I have hereunto set my hand this 11th day of March, 1932.

GUSTAF A. JOHNSON. 

